The Certified Norton Spherical gas diffuser stones meet the certification requirements for the ASTM D892? foam methods.
Based on the geometrical shape alone, spherical gas diffuser stones produce larger bubbles, that tend to coalesce much easier forming larger bubbles causing the foam to break more easily, thus giving slightly better results. Permeability and porosity of diffusers change over time it is therefore recommended to test them periodically preferably after each use.
